Flat elongated objects, such as metal strip, may be treated with a variety of liquid substances, such as pickling agents, alkali washes, rinsing solutions etc., for continuous processing. One such use of metal strip in a continuous process is the formation of tubing, such as the process described in U.S. Pat. No. 3,122,114. When the metal strip is treated with such a liquid substance in a continuous process, it is usually necessary that the substance be substantially removed prior to downstream strip processing. Generally there is some oscillation of the traveling strip as it is driven along its pathway, and an effective wiping device should maintain surface contact between a wiping surface and the surfaces of the strip notwithstanding such oscillations.
Heretofore, the most commonly used apparatus for wiping continuously moving strip included rollers positioned to run along the surfaces of the continuously moving strip. As a result of oscillating or weaving both laterally and up and down, it was difficult to position such rollers and apply an appropriate amount of pressure to such rollers to hold them in continuous contact with the surfaces of the strip, and uneven wiping often resulted from poor roller-strip surface contact. Another disadvantage of rollers was that they tended to be cut by the sharp edges of the metal strip thus requiring frequent replacement.
Effective wiping of a flat surface, such as the surfaces of metal strip, may also be effected with a resilient blade, such as a rubber blade. However, resilient blades become worn during use and tend to decrease contact with the strip surface thus reducing wiping efficiency. Eventually the wiping blade must be replaced entirely. In a continuous multistep process, such as forming tubing from strip steel, it is highly disadvantageous to have to stop the process for a detail, albeit important detail, such as wiper blade replacement. Accordingly, it is desirable that an in-line wiping device maintain surface contact of the blade against the strip surface even as the blade wears down and for in-line replacement of the blade when it is worn beyond its usefulness.